This invention relates to a method for smoothing out the flow rate of refuse and for providing surge capacity in a refuse feed system.
It is common in the chemical process industry to require that a continuous process operate with a constant and uniform feed originating from a source which produces the feed at a variable or intermittent rate. In the processing of fluids, smoothing out of the flow rate may be done simply by the use of a surge tank in the system. For solid materials, the same effect can be obtained by use of a feed hopper or a live bottom bin. However, neither of these techniques is satisfactory in the feeding of raw or shredded refuse, since refuse has a tendency to settle and compact, if stored in an immobile condition. Attempts at creating an inventory of refuse by storing and transporting this material through a conventional storage hopper tend to result in the material bridging or jamming in the hopper. Consequently, conventional storage or surge systems have been found unsatisfactory for smoothing out the flow of refuse which normally originates from a source which produces it at a variable or intermittent rate, e.g. a dump truck or a refuse shredder.
A conventional means for transferring refuse from a storage area of a refuse treatment plant to a furnace, incinerator or converter is a continuous flow conveyor. Screw and bucket conveyors are also used, but these devices do not generally have the capacity of continuous flow conveyors. Powell et al., in U.S. Pat. No. 3,926,582 discloses a typical continuous conveyor for feeding refuse to a shaft furnace. A conveyor system normally comprises a horizontal section and an inclined section. These may be composed of a single unit or two separate units. If employing a single unit, care must be taken not to deposit too much refuse on the device. However, neither single nor double unit conveyors can successfully store a significant amount of refuse inventory, nor can they handle sudden surges of feed dumped on the conveyor, nor smoothen out the flow of the refuse since they contain no surge capacity.